Is the flight to Spain turbulent?
Most of the crossing is smooth. The main source of bumps is the North Atlantic jet stream, which flights to Madrid and Barcelona cross at cruise, causing occasional clear-air turbulence. The southern great-circle route to Spain is often calmer than the northern routes to the UK and Ireland.
When is the smoothest time to fly to Spain?
May through September generally has a weaker, more northerly jet stream and the calmest transatlantic air. Winter brings a stronger jet and more clear-air turbulence, plus occasional Atlantic storm systems near the Iberian coast.
Why is there turbulence over the Atlantic?
The North Atlantic jet stream — a fast river of air at cruise altitude — creates wind shear at its edges that can jolt an aircraft without warning (clear-air turbulence, or CAT). It is strongest in winter and on the eastbound US→Europe leg, which rides the jet. Pilots change altitude to find smoother air, but CAT is invisible on radar, so it is the main reason to keep your belt on.
Where should I sit on a flight to Spain?
Over the wing, near the aircraft's center of gravity, gives the steadiest ride. Keep your seatbelt fastened even when the sign is off — clear-air turbulence over the Atlantic can appear suddenly. Overnight eastbound flights often cross the jet stream while you are sleeping, so belt over the blanket.